The present invention relates to cutting inserts and, more particularly, to milling inserts having surfaces designed for supporting of the insert relative to a milling cutter body, and a milling tool.
In machining of metal, such as during milling operations with a rotating tool having indexable and/or replaceable milling inserts, it is important to keep the milling inserts securely and accurately positioned relative to the milling cutter body. If an insert is not properly positioned or shifts slightly from its intended position during machining, it can result in damage to a workpiece and/or to the insert. Secure mounting of triangular or trigon inserts, such as WO2011/089552, can be problematic because, typically, a point of the triangle is oriented for performing a cutting operation, and the flat (or, in the case of a trigon, convex) side surface opposite the point must abut a side wall of a pocket of a milling cutter body to prevent the insert from moving relative to the milling cutter body. Because there may not be as many points of contact between the insert and the side wall of the milling cutter body as desired, or because the insert may have the ability to rotate slightly relative to the walls of the pocket, it can be difficult to properly position such inserts, or to maintain them in position once mounted.
Some inserts are provided with complex shapes on their bottom surfaces, and these complex shapes mate with similar, inverse complex shapes on the bottom surface of the milling cutter body pocket. In this way, the mating complex shapes facilitate preventing the insert from moving relative to the milling cutter body. A problem with such shapes, however, is that they can interfere with good contact between side supporting surfaces of the insert and side abutment surfaces of the milling cutter body pocket.
It is desirable to provide a milling insert that be securely and accurately mounted to a milling cutter body and that resists movement due to cutting forces during machining.
A milling insert according to an aspect of the present invention comprises a first end surface, a second end surface, a side surface extending between the first end surface and the second end surface, at least one cutting edge defined by an intersection of at least one of the first end surface and the second end surface with the side surface, the at least one cutting edge comprising a radiused component having a first end and a second end and first and second components at the first and the second ends of the radiused component, respectively, the first and second components being less curved than the radiused component, wherein the side surface comprises at least one concave valley formed by first and second support surfaces.